Air-cooled system



Oct. 14, 1958 N. A. ZEHNDER 2,855,762

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2,855,762 AIR-COOLED SYSTEM Norbert A. Zehnder, Winterthur, Switzerland, assignor to Sulzer Fret-es S. A. Winterthur Switzerland a co oration of Switzerland rp The present invention relates to a system including an air-cooled chamber having a wall and an opening in the wall for providing access to the chamber, and a closure for said opening which closure is formed by a flowing sheet of relatively warm air.

An object of the invention is to provide a system of the type described supra in which losses of cold from the chamber to the outside are reduced and the cost of producing warm air for effecting the closure is minimized.

The system according to the invention includes an air cooling plant in which a refrigerant is compressed in a compressor, cooled in an air cooled cooler, expanded, heated in a heat exchanger by air to be cooled, and returned to the compressor. The air which is cooled by heating the expanded refrigerant is introduced into the chamber and is preferably conducted, prior to removal 1 from the chamber, adjacent to the opening in the front wall of the chamber in parallel relation to the warm air stream forming the closure. The warm air which forms the so-called air curtain is the air which has been used for cooling the refrigerant in the air cooler and is ,preferably returned to the air cooler after it has formed the air curtain. In this way any cold air which would otherwise escape through the opening is not only picked up by the warm air but returns in a cooled condition to the air cooler, affording more efficient operation of the latter. The warm air emerging from the cooler for the refrigerant is preferably conducted through at least a part of the side walls and of the top wall as well as through the front wall of the chamber thereby providing an elficient insulation of these walls.

The invention is particularly suitable for use in connection with refrigerated display counters and can beused with great advantage in display counters in which merchandise is placed on shelves which are accessible through the warm air screened opening for removal of the merchandise by the customer. The shelves are preferably made accessible from the rear of the chamber for refilling the shelves with merchandise without disturbing the customers inspecting or removing merchandise. The cooling air is blown into the shelves from the side walls of the chamber and leaves the shelves adjacent to the front wall. The still very cool air is withdrawn from the chamber through an opening in or near the floor of the chamber and adjacent to the bottom of the opening. Cool air will therefore tend to escape through the opening in the front wall of the chamber causing a loss of cold. Besides, it is uncomfortable for a person reaching through the opening into the shelves if the hand and arm must pass through a rather extended space in which cold .air circulates. The invention therefore provides a curtain of relatively warm air closing the opening and forcing the cold air which otherwise would escape through the opening downward and into a grill adjacent to the bottom of the opening. In this way loss of cold is substantially reduced and the arm of the person reaching into the shelves passes through comfortably warm air and through a very small space in which cold air moves relatively slowly. The cold ab- 2,855,762 Patented Oct. 14, 1958 sorbed by the warm air forming the curtain and moving at relatively great velocity is not lost because, according to the invention, the air is used as coolant for the refrigerant.

The novel features which are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself however and additional objects and advantages thereof will best be understood from the following description of. embodiments thereof when read in connection with the accompanying drawing in which:

Figure 1 is a diagram showing the circuits of the refrigerant, of the cold air and of the warm air and their interrelations;

Figure 2 is a plan view of the basement of a plant in which the system according to the invention is applied to a refrigerated display counter;

Figure 3 is a sectional view through a-plant according to the invention of which the basement is shown in Figure 2, the section being made along line III-III in Figure2;

Figure 4 is a vertical section of a plant according to the invention, the section being made along line IV-IV in Figure 2;

Figure 5 is a vertical section of the plant according to the invention made along line V-V in Figure 2.

Figure 6 is a vertical section of a plant accordingto the invention made along line VI-VI in Figure 2.

Like partsare designated by like numerals in different figures of the drawing.

Referring more particularly to Figure 1, numeral 1 designates a space or chamber into which cooled air is conducted through apertures 15 from a duct 14. The cold air is removed from the chamber through apertures 4 in or near the floor of the chamber and adjacent to the wall of the chamber which is provided with an opening 5 providing access to the chamber. The latter has a top wall 32 and a rear wall 31 placed opposite the openingfS. The cold air leaving the chamber is conducted through a conduit16, in which an air filter 11 is provided, into a cooler 12 which is cooled in the conventional manner by means of an expanded and evaporating refrigerant. The cooled air leaves the cooler 12 through the aforementioned conduit or duct 14 in which a circulating pump 13 is interposed.

. The conventional circuit of the refrigerant includes a compressor 9, forcing the refrigerant through a heat exchanger 6 in which the compressed refrigerant is cooled and condemned by indirect heat exchange with air. The refrigerant passes through a vessel 8 and is expanded and heated by the air passing through the cooler 12 and returned to the compressor 9.

The air which absorbs heat from the refrigerant in the heat exchanger 6 and is thereby heated, passes through a conduit 10, in which a blower 7 is interposed, into an air box 17 at the top of the opening 5. The warm air leaves thebox 17 through a grill 2 and moves at relatively great velocity in the form of a sheet or curtain intoagrill 3 at the bottom of the opening 5 and is therefrom returned through a conduit 18, in which' a filter 19 is; interposed, to the heat exchanger 6. I

Figures 2 to 6 illustrate the application of the invention to a refrigerated display counter.

Figure 2 is a plan view of the basement below the floor on which the counter is placed. Numeral 18' designates an air duct conducting air through a filter 19 into a heat exchanger 6, cooling a refrigerant received from a coma pressor 9'. The air which is heated in the heat exchanger 6' is allowed to escape into the basement, if the latter is closed and is sucked into fans 7 and 7". If desired, ducts may be provided between the heat exchanger and the fans, as shown in Figure 1. The air travels from the fans 7 and 7" through ducts 10' and 10", respectively, upwards into hollow side wall portions 19 and 20, respectively, of a chamber 1 and therefrom through a hollow top wall portion 21 of the chamber. Therefrom the warm air travels through the hollow upper portion of a front wall 22. The lower end of this front wall which forms the top of an opening 5' is provided with a grill 2' from which the air emerges in a Stratified downward stream of relatively great velocity. The air is received by a grill 3' at the bottom of the opening 5' and is returned therefrom through the duct 18 in the basement to the cooler 6'.

A plurality of substantially horizontal shelve plates 23 are placed in spaced parallel relation inside the chamber 1. The front edges and rear edges 33 and 34 respectively of the plates 23 are relatively little spaced from the front wall 22 and the opening 5'. The front edges and rear edges 33 and 34 respectively of the plates 23 are relatively widely spaced from the rear wall 24 of the chamber 1', permitting a person to move in the space 35 between the shelves and the rear wall for filling the shelves with merchandise which is removed from the shelves by reaching thereinto through the opening 5. To facilitate these operations, the shelves which are at the level of the opening 5' may be slightly declined toward the opening 5'. The shelves which are at a level higher than the opening 5 may be inclined in the opposite direction, so that merchandise can be pushed thereonto for temporary storage from the rear of the shelves and the merchandise tends to roll or slide toward the rear when it is removed from the upper shelves for placing it on the lower shelves. The forward portions of the shelves may be subdivided by vertical partitions 26. The forward portions of the sides of the shelves or rack formed by the plates 23 are closed by hollow side wall portions 19 and 20. The rear portions of the sides of the rack are spaced from the side walls of the chamber 1' and are closed by lateral walls 27 and 28 whose lower portions are provided with relatively small openings and 15, respectively, and whose upper portions are provided with relatively wide openings.

The cold air emerges from a cooler 12' in the basement, the cooler being cooled by a refrigerant received from the heat exchanger 6', after passage through a vessel 8', as shown in the circuit diagram Figure 1. The cold air is pumped by a blower 13' into ducts 14' and 14" which terminate in the chamber 1 adjacent to the rear portions 29 and 30 of the side wallsof the chamber 1. The cold air passes through the openings 15 and 15" in the walls 27 and 28, passes between the shelve plates 23, moving forward and then downward in the space 36 between the front of the rack and the front wall of the chamber 1'. The warm air flowing from the grill 2' to the grill 3 prevents escape of cold air throughthe opening 5'. The cold air flowing downward along the inside of the front wall 22-and the opening 5 is received in a grill 4' from which it flows through a duct 16' in the basement, through a filter 11', and back into the cooler '12.

What is claimed is:

V 1. An-air-cooled system comprising, in combination, a chamber having at least one substantially vertical wall, an opening in said wall, said opening having a top portion and a bottom portion, an air-cooling plant in which a refrigerant is compressed in a compressor, cooled in an air-cooledcooler, expanded, heated in a heat exchanger by air to be cooled, and returned to the compressor, cooling air conduit means connected 'withsaid heat exchanger and with said chamber for conducting cooled air "from said heat exchanger into said chamber, a coolingair removal conduit connected with said chamber adjacent to said wall for removing cooling air from said chamber, a warm air conduit connected with-said cooler and terminating in said chamber adjacent to one portion of said opening, and a warm air return conduit connected with said chamber adjacent to the other portion of said opening and being connected with said cooler for returning air thereto.

2. An air-cooled system as defined in claim 1 in which said warm air conduit terminates adjacent to said top portion of said opening and said air return conduit is connected with said bottom portion of said opening.

3. An air-cooled system as defined in claim 1, including a plurality of superimposed substantially horizontal shelves placed inside said chamber, the latter having a rear wall placed opposite said substantially vertical wall, said chamber having two side walls, and cooling air conduit means terminating adjacent to said side walls for discharging cooling air laterally onto said shelves.

4. An air-cooled system according to claim 3 in which said shelves are spaced from said substantially vertical wall, the cooling air flowing from said shelves into the space between said shelves and said substantially vertical wall and travelling in said space parallel to the warm air at a speed which is slow relatively to the speed of travel of the warm air.

5. An air-cooled system according to claim 3 in which said shelves have a front edge which is relatively little spaced from said substantially vertical wall, the cooling air flowing from said shelves into the space between said shelves and said substantially vertical wall and travelling in said space parallel to the warm air, said shelves having a rear edge which is relatively widely spaced from said rear wall permitting movement of a person between the shelves and said rear wall and filling of the shelves with merchandise by said person, which merchandise can be removed by reaching through said opening and the space between the substantially vertical wall and said shelves.

6. An air-cooled system comprising a chamber having a substantially vertical front wall, a rear wall, two side walls, a top wall, and a floor, substantially horizontal shelves placed inside said chamber and having marginal portions spaced from said walls, an air-cooling plant in which a refrigerant is compressed in a compressor, cooled in an air-cooled cooler, expanded, heated in a heat exchanger by air to be cooled, and returned to the compressor, cooling air conduit means connected with said heat exchanger and terminating in the floor of said chamber adjacent to said side walls for conducting air cooled in said heat exchanger into said chamber and laterally into said shelves, said front wall having an opening providing access to said shelves and having a bottom and a top, a cooling air removal conduit connected with said chamber adjacent to the lower portion of said front wall, for removing cooling air from said chamber, a warm air supply-conduit connected with said cooler and terminating in said chamber adjacent to the top of said opening, and a warm air removal conduit connected with said chamber adjacent to the bottom of said opening.

7. An air-cooled system according to claim 6 in which said chamber has a hollow front wall located above said opening and a top wall having a hollow portion, said side walls having each a hollow portion, said warm air supply conduit being formed by said hollow portions of said side walls and of said top wall and by said hollow front wall.

,8. An air-cooled system according to claim 6, including a basement located below said floor, said air-cooling plant being located in said basement.

References Cited in the file of this patent UNITED STATES PATENTS 1,173,555 Caldwell Feb. 29, 1916 2,209,431 Tull July 30, 1940 12,241,854 Hall May 13, l94l 2,558,997 Voelker July 3, 1951 

